<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<style>
			.outerdiv{
				border: 1px solid red;
				width: 400px;
				height: 300px;
				/*padding: 30px;*/
				/*外边距设置居中*/
				margin: 0px auto;
			}
			.innerdiv{
				border: 1px solid darkblue;
				width: 150px;
				height: 150px;
			 	margin: 30px;
			 	/*设置内框在大框居中*/
			 	margin: 50px auto;
			}
		</style>
	</head>
	<body>
		<div class="outerdiv">
			<div class="innerdiv">
				sanchredh
			</div>
		</div>
	</body>
</html>
